\inmodule QtDBus More...

#include <qdbuspendingreply.h>

Inheritance diagram for QDBusPendingReply< Types >:

Collaboration diagram for QDBusPendingReply< Types >:

Public Types
enum	{ Count = std::is_same_v<typename Select<0>::Type, void> ? 0 : sizeof...(Types) }

Public Member Functions
constexpr int	count () const
	Return the number of arguments the reply is supposed to have.
	QDBusPendingReply ()=default
	Creates an empty QDBusPendingReply object.
Q_IMPLICIT	QDBusPendingReply (const QDBusPendingCall &call)
	Creates a QDBusPendingReply object that will take its contents from the call pending asynchronous call.
Q_IMPLICIT	QDBusPendingReply (const QDBusMessage &message)
	Creates a QDBusPendingReply object that will take its contents from the message message.
QDBusPendingReply &	operator= (const QDBusPendingCall &call)
	Makes this object take its contents from the call pending call and drops the reference to the current pending call.
QDBusPendingReply &	operator= (const QDBusMessage &message)
	Makes this object take its contents from the message message and drops the reference to the current pending call.
template<int Index>
Select< Index >::Type	argumentAt () const
	Returns the argument at position index in the reply's contents.
Select< 0 >::Type	value () const
	Returns the first argument in this reply, cast to type `Types`[0] (the first template parameter of this class).
	operator typename Select< 0 >::Type () const
	Returns the first argument in this reply, cast to type `Types`[0] (the first template parameter of this class).
QVariant	argumentAt (int index) const
Public Member Functions inherited from QDBusPendingCall
	QDBusPendingCall (const QDBusPendingCall &other)
	Creates a copy of the other pending asynchronous call.
	QDBusPendingCall (QDBusPendingCall &&other) noexcept=default
	~QDBusPendingCall ()
	Destroys this copy of the QDBusPendingCall object.
QDBusPendingCall &	operator= (QDBusPendingCall &&other) noexcept
QDBusPendingCall &	operator= (const QDBusPendingCall &other)
	Creates a copy of the other pending asynchronous call and drops the reference to the previously-referenced call.
void	swap (QDBusPendingCall &other) noexcept
bool	isFinished () const
void	waitForFinished ()
bool	isError () const
bool	isValid () const
QDBusError	error () const
QDBusMessage	reply () const

Friends
class	::tst_QDBusPendingReply

Additional Inherited Members
Static Public Member Functions inherited from QDBusPendingCall
static QDBusPendingCall	fromError (const QDBusError &error)
static QDBusPendingCall	fromCompletedCall (const QDBusMessage &message)
Protected Member Functions inherited from QDBusPendingReplyBase
	QDBusPendingReplyBase ()
void	assign (const QDBusPendingCall &call)
void	assign (const QDBusMessage &message)
QVariant	argumentAt (int index) const
void	setMetaTypes (int count, const QMetaType *metaTypes)
Protected Member Functions inherited from QDBusPendingCall
	QDBusPendingCall (QDBusPendingCallPrivate *dd)
Protected Attributes inherited from QDBusPendingCall
QExplicitlySharedDataPointer< QDBusPendingCallPrivate >	d

Detailed Description

template<typename... Types>
class QDBusPendingReply< Types >

\inmodule QtDBus

Since: 4.5

The QDBusPendingReply class contains the reply to an asynchronous method call.

The QDBusPendingReply is a variadic template class. The template parameters are the types that will be used to extract the contents of the reply's data.

This class is similar in functionality to QDBusReply, but with two important differences:

\list

QDBusReply accepts exactly one return type, whereas QDBusPendingReply can have any number of types
QDBusReply only works on already completed replies, whereas QDBusPendingReply allows one to wait for replies from pending calls \endlist

Where with QDBusReply you would write:

QDBusReply<QString> reply = interface->call("RemoteMethod");
if (reply.isValid())
    // use the returned value
    useValue(reply.value());
else
    // call failed. Show an error condition.
    showError(reply.error());

with QDBusPendingReply, the equivalent code (including the blocking wait for the reply) would be:

    QDBusPendingReply<QString> reply = iface->asyncCall("RemoteMethod");
    reply.waitForFinished();
    if (reply.isError())
        // call failed. Show an error condition.
        showErrorD(reply.error());
    else
        // use the returned value
        useValue(reply.value());

For method calls that have more than one output argument, with QDBusReply, you would write:

reply = interface->call("RemoteMethod");

whereas with QDBusPendingReply, all of the output arguments should be template parameters:

    QDBusPendingReply<bool, QString> reply = iface->asyncCall("RemoteMethod");
    reply.waitForFinished();
    if (!reply.isError()) {
        if (reply.argumentAt<0>())
            showSuccess(reply.argumentAt<1>());
        else
            showFailure(reply.argumentAt<1>());
    }

QDBusPendingReply objects can be associated with QDBusPendingCallWatcher objects, which emit signals when the reply arrives.

See also: QDBusPendingCallWatcher, QDBusReply

Definition at line 60 of file qdbuspendingreply.h.

Member Enumeration Documentation

◆ anonymous enum

template<typename... Types>

anonymous enum

Enumerator
Count

Definition at line 65 of file qdbuspendingreply.h.

Constructor & Destructor Documentation

◆ QDBusPendingReply() [1/3]

template<typename... Types>

QDBusPendingReply< Types >::QDBusPendingReply ( )

inlinedefault

Creates an empty QDBusPendingReply object.

Without assigning a QDBusPendingCall object to this reply, QDBusPendingReply cannot do anything. All functions return their failure values.

◆ QDBusPendingReply() [2/3]

template<typename... Types>

Q_IMPLICIT QDBusPendingReply< Types >::QDBusPendingReply ( const QDBusPendingCall & call )

inline

Creates a QDBusPendingReply object that will take its contents from the call pending asynchronous call.

This QDBusPendingReply object will share the same pending call reference as call.

Definition at line 72 of file qdbuspendingreply.h.

◆ QDBusPendingReply() [3/3]

template<typename... Types>

Q_IMPLICIT QDBusPendingReply< Types >::QDBusPendingReply ( const QDBusMessage & message )

inline

Creates a QDBusPendingReply object that will take its contents from the message message.

In this case, this object will be already in its finished state and the reply's contents will be accessible.

See also: isFinished()

Definition at line 74 of file qdbuspendingreply.h.

Member Function Documentation

◆ argumentAt() [1/2]

template<typename... Types>

template<int Index>

Select< Index >::Type QDBusPendingReply< Types >::argumentAt ( ) const

inline

Returns the argument at position index in the reply's contents.

If the reply doesn't have that many elements, this function's return value is undefined (will probably cause an assertion failure), so it is important to verify that the processing is finished and the reply is valid.

If the reply does not contain an argument at position index or if the reply was an error, this function returns an invalid QVariant. Since D-Bus messages can never contain invalid QVariants, this return can be used to detect an error condition.

Definition at line 84 of file qdbuspendingreply.h.

References Count.

◆ argumentAt() [2/2]

template<typename... Types>

QVariant QDBusPendingReplyBase::argumentAt ( int index ) const

Definition at line 34 of file qdbuspendingreply.cpp.

◆ count()

template<typename... Types>

int QDBusPendingReply< Types >::count ( ) const

inlineconstexpr

Return the number of arguments the reply is supposed to have.

This number matches the number of non-void template parameters in this class.

If the reply arrives with a different number of arguments (or with different types), it will be transformed into an error reply indicating a bad signature.

Definition at line 67 of file qdbuspendingreply.h.

References Count.

◆ operator typename Select< 0 >::Type()

template<typename... Types>

QDBusPendingReply< Types >::operator typename Select< 0 >::Type ( ) const

inline

Returns the first argument in this reply, cast to type Types[0] (the first template parameter of this class).

This is equivalent to calling argumentAt<0>().

This function is provided as a convenience, matching the QDBusReply::value() function.

Note that, if the reply hasn't arrived, this function causes the calling thread to block until the reply is processed.

If the reply is an error reply, this function returns a default-constructed Types[0] object, which may be indistinguishable from a valid value. To reliably determine whether the message was an error, use isError().

Definition at line 107 of file qdbuspendingreply.h.

◆ operator=() [1/2]

template<typename... Types>

QDBusPendingReply & QDBusPendingReply< Types >::operator= ( const QDBusMessage & message )

inline

Makes this object take its contents from the message message and drops the reference to the current pending call.

If the current reference is to an unfinished pending call and this is the last reference, the pending call will be canceled and there will be no way of retrieving the reply's contents, when they arrive.

After this function is finished, the QDBusPendingReply object will be in its "finished" state and the message contents will be accessible.

See also: isFinished()

Definition at line 79 of file qdbuspendingreply.h.

◆ operator=() [2/2]

template<typename... Types>

QDBusPendingReply & QDBusPendingReply< Types >::operator= ( const QDBusPendingCall & call )

inline

Makes this object take its contents from the call pending call and drops the reference to the current pending call.

If the current reference is to an unfinished pending call and this is the last reference, the pending call will be canceled and there will be no way of retrieving the reply's contents, when they arrive.

Definition at line 77 of file qdbuspendingreply.h.

◆ value()

template<typename... Types>

Select< 0 >::Type QDBusPendingReply< Types >::value ( ) const

inline

Returns the first argument in this reply, cast to type Types[0] (the first template parameter of this class).

This is equivalent to calling argumentAt<0>().

This function is provided as a convenience, matching the QDBusReply::value() function.

Note that, if the reply hasn't arrived, this function causes the calling thread to block until the reply is processed.

If the reply is an error reply, this function returns a default-constructed Types[0] object, which may be indistinguishable from a valid value. To reliably determine whether the message was an error, use isError().

Definition at line 102 of file qdbuspendingreply.h.

◆ ::tst_QDBusPendingReply

template<typename... Types>

friend class ::tst_QDBusPendingReply

friend

Definition at line 62 of file qdbuspendingreply.h.

The documentation for this class was generated from the following files:

qtbase/src/dbus/qdbuspendingreply.h (70fa17fcb832f187bdaf0edad9cdcef32053e15f)
qtbase/src/dbus/qdbuspendingreply.cpp (9fd9845d1f631169b46457cfa3f7e8aee5347459)

Public Types

Public Member Functions

Friends

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

◆ anonymous enum

Constructor & Destructor Documentation

◆ QDBusPendingReply() [1/3]

◆ QDBusPendingReply() [2/3]

◆ QDBusPendingReply() [3/3]

Member Function Documentation

◆ argumentAt() [1/2]

◆ argumentAt() [2/2]

◆ count()

◆ operator typename Select< 0 >::Type()

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ value()

Friends And Related Symbol Documentation

◆ ::tst_QDBusPendingReply